Glare Node not act as Expected
The glare node works based on a threshold value. Meaning only the pixels that have values larger than the set value will be affected by glare/bloom/glow.
Use a lower value until you get what you need.
Also, keep the mix at $0$. If you set it to $-1$ you are actually cancelling the effect completely.

Mix
Value to control how much of the effect is added on to the image. A value of -1 would give just the original image, $0$ gives a $50/50$ mix, and $1$ gives just the effect.
Threshold
Pixels brighter than this value will be affected by the glare filter.

(Form the blender manual)
Read Control light halos in the compositor based on emission level